In this chapter we review
trauma-related studies involving
epinephrine (E),
norepinephrine (NE), and
serotonin (5-HT). Central
catecholamine neurons seem to play a critical role in level of alertness, vigilance, orienting, selective attention, memory, fear conditioning, and cardiovascular responses to life-threatening stimuli. Evidence of
catecholamine dysregulation in
post-traumatic stress disorder (
PTSD) includes exaggerated increases in heart rate and blood pressure when exposed to visual and auditory reminders of
trauma, elevated 24-hour urine
catecholamine excretion, decreased platelet
alpha-2 adrenergic receptor number, exaggerated behavioral, cardiovascular, and biochemical responses to IY
yohimbine, decreased cortical brain metabolism secondary to IV
yohimbine, and clinical efficacy of
adrenergic blocking agents.
Serotonin seems to play numerous roles in the central nervous system, including regulation of sleep, aggression, appetite, cardiovascular and respiratory activity, motor output, anxiety, mood, neuroendocrine secretion, and
analgesia. Evidence of serotonergic dysregulation in
PTSD includes frequent symptoms of aggression, impulsivity, depression and suicidality, decreased platelet
paroxetine binding, blunted
prolactin response to
fenfluramine, exaggerated reactivity to m-chloro-phenyl-
piperazine, and clinical efficacy of
serotonin reuptake inhibitors. It has been suggested that alterations in NE, E, and
5-HT may have relevance for symptoms commonly seen in survivors with
PTSD, including hypervigilance, exaggerated startle, irritability, impulsivity, aggression, intrusive memories, depressed mood, and suicidality.